The present invention relates to bearing apparatus, more particularly bearing apparatus for mounting submarine mast fairing structures.
Submarine vessels have conventionally been constructed with one or more elevated structures or vertical projections situated above the main deck or superstructure. These mast structures have housed various functional items, such as navigational bridges, observation or conning towers, periscopes, antennas, snorkels and armaments.
In order to reduce consequent deleterious hydrodynamic, buoyant and even aerodynamic effects of such mast structures, auxiliary submarine structures commonly referred to as "mast fairings" have conventionally been built so as to enclose or surround the mast structures. As early as 1911, for example, U.S. Pat. No. 1,072,393 for "Submersible-Boat Construction" recognized the benefit of providing auxiliary structure of this nature, a "tapered fairwater" which serves to "decrease the resistance of the projecting parts, especially while running submerged." (U.S. Pat. No. 1,072,393, page 1, lines 37-42).
The established practice for mounting a submarine mast fairing involves direct contact of the fairing with a bearing which is attached to the submarine sail structure; i.e., each bearing is run directly against the outer side of the fairing skin. This approach, however, has some drawbacks. It is noted that the conventionally used materials for the mast fairing and the structural bearing do not lend themselves, in combination, to this bearing-on-fairing configuration. Typically, the mast fairing is made of a composite material such as fiberglass, while the structural bearing is made of a metallic material or a plastic or resin material such as ultra high molecular weight polyethelene. The fiberglass material and ultra high molecular weight polyethelene, for example, are not suitable for being combined in this manner in terms of both wear and noise; notably, the fiberglass material in and of itself does not provide a good bearing surface and is qualitatively lacking for this purpose. Wear and noise are markedly heightened for submarine mast fairings which are retractable--i.e., fairings which ride up and down while housed within the submarine sail.
The resultant wearing down of the fairing in accordance with this conventional bearing-on-fairing configuration all too frequently necessitates reconditioning or replacement of the fairing. The reconditioning process is laborious, expensive and time-consuming. The useful life expectancy of the fairing is limited, as the fairing will eventually be worn to the point that it falls to meet thickness and strength requirements.
The heavy wear upon the fairing and structural bearing in this bearing configuration aggravates the acoustic signature of the submarine, especially during retractile movement of the fairing system. This conventional approach is acoustically deficient for the additional reason that it is detrimental and hindering to communications systems located in modern submarine sails.